I'm currently taking a Coursera course (in the 2nd of 4 weeks today) called Getting and Cleaning Data (https://class.coursera.org/getdata-002). I think the lectures for week 2 might answer your question.

If you're using a Windows machine, you may want to generate a powershell (using system.net.webclient) script that is run from R.

see the following links for some info...

http://msdn.microsoft.com/en-us/library/system.net.webclient.aspx

http://technet.microsoft.com/en-us/library/bb978526.aspx

and some code to get you started:

sink("download.bat")

cat("powershell -File \"r-generated.ps1\"")

sink()

sink("r-generated.ps1")

cat("$wc=new-object system.net.webclient\n")

#download 'your_url_here' and save as temp.html in the working directory

cat(paste("$wc.downloadfile(\"", your_url_here, "\", \"", gsub("/", "\\\\", getwd()), "\\temp.html\")\n", sep = ""))

sink()

shell("download.bat")

twitteR library : cran.r-project.org/web/packages/twitteR/twitteR.pdf‎

many examples are given here : http://www.r-bloggers.com/search/twitter

note that the twitter API has now many limitations

Thanks all, I used QVsouce tool to collect tweets, It can also be done using twitteR package.